Debbie Bosanek, who has worked for Buffett for nearly two decades, has become a symbol in the White House’s fight over the tax code and economic fairness. Obama is expected to renew his push for the so-called “Buffett rule” that would bring investment taxation levels into line with income taxation levels — and ensure that upper income earners pay rates as high as middle-class Americans.

“Warren Buffett’s secretary shouldn’t pay a higher tax rate than Warren Buffett,” President Obama said in September, when he unveiled his American Jobs Act proposal. It’s a trope that Buffett himself has repeated, as he has campaigned for higher taxes on investment income.